1. Field of the Invention
The present invention relates to an apparatus and method for removing bones from a fish and, more specifically, for removing pin bones from a fillet of salmon, pollack, mackerel, trout, whitefish, haddock, scrod, and the like.
2. Background Art
Fish possess a skeletal structure that has a vertebral column, or back bone, from which spines extend upwardly (dorsal spines) and downwardly (ventral spines). No ventral spines are located in the region of the fish""s belly cavity, however. Vertebrae extend over the top of the belly cavity for a short distance on either side of the mid-line, from which rib bones depend and curve downwardly to enclose the belly. Pin bones extend horizontally from the rib bones and terminate at or near the skin. There are about forty pin bones in salmon.
The normal method of filleting fish, by hand or machine, is to cut through the fish following the line of the bones from the dorsal to ventral fins and to pass over the rib bones, which severs the connections between the pin bones and the rib bones. Thus, a line of pin bones remains in the fillet.
There are two methods commonly used to remove the remaining pin bones from the fillet: cutting out the pin bones or pulling them out. For the first option, filleting machines exist in the prior art that can produce bone-free fish fillets, but the yield is substantially lowered since the whole belly flap is cut off to ensure complete removal of the pin bones. The flesh of the belly flap can be recovered in a minced form after its passage through a bone separating device.
However, since salmon and other fish are expensive, removal of the pin bones without extracting substantial quantities of meat is desired. Thus, the second option of pin bone removal is used, which is to pull the bones out of the fillet. The oldest technique is pulling out the bones using a gripping tool, such as pliers. However, this option is time-consuming and labor-intensive, which results in higher cost to the consumer and potential injuries to the workers, such as carpal tunnel syndrome.
Therefore, a need exists in the art for a relatively inexpensive device to remove pin bones from fish. It is desired that the device can be used in an automated process, instead of having an operator who removes the bones by manually maneuvering a machine. Still another need in the art is for a device that reliably extracts the pin bones without removing a significant amount of meat from the fillet, creating an unattractive surface appearance, or otherwise damaging the fillet.
New apparatus and method have been developed to meet these and other needs in the art. U.S. patent application Ser. No. 09/253,262, which is incorporated herein in its entirety by reference, in one aspect discloses an apparatus and method utilizing a plurality of substantially identical, spring-tempered sheet metal disks that each has a periphery that can be linear or non-linear to removing pin bones. The disks are assembled on a splined shaft to form a stack of the disks aligned so that the peripheries form an alternating pattern of xe2x80x9cpinch-points,xe2x80x9d in which the periphery of two disks contact each other, and gaps, in which the peripheries are separated from each other.
The present invention relates to removing pin bones from a fillet of salmon, pollack, mackerel, trout, whitefish, haddock, scrod, and the like. The present invention, in one aspect, relates to an apparatus and method for removing a pin bone or pin bones from a fillet or like which use a rotating assembly or stack of individual disks that are engaged by a shaft, oscillate axially and are timed to alternately tilt in a rapid fashion so as to effect the action of multiple pairs of tweezers. The pin bone is disposed between a pair of tweezer or two adjacent rotating disks and pulled out of the fillet by the rotating disks. The rotating stack of individual disks operates at different speeds in an operation circle to enhance the operational efficiency. Various types of disks, such as disks disclosed in U.S. patent application Ser. No. 09/253,262 and disks existing in the prior art, can be utilized in the present invention.
Accordingly, in one aspect the present invention provides a pin bone removal apparatus comprising a frame having a first end and an opposed second end defining an axis therebetween, a plurality of disks, each disk having a center, a periphery circumscribing the center to form an opening, a diameter, a first side, and an opposed second side, and a shaft positioned between the first end and the second end of the frame and rotatable around the axis of the frame. The shaft has a circumference of a size to be complementarily received by and disposed through the opening in each disk to form a stack of the disks having a longitudinal axis substantially parallel to the axis of the frame. The apparatus further includes a first movable arm and a second movable arm positioned apart from the first movable arm thereby to define a space therebetween for receiving the stack of the disks therein. The first and second movable arms can move synchronously along the axis of the frame to cause the stack of the disks to move along with them to process a fillet or fillets.
In another aspect, the present invention provides a pin bone removal apparatus comprising a frame having a first end and an opposed second end defining an axis therebetween, a plurality of disks, each disk having a center, a periphery circumscribing the center to form an opening, a diameter, a first side, and an opposed second side, and a shaft positioned between the first end and the second end of the frame and rotatable around the axis of the frame. The shaft has a circumference of a size to be complementarily received by and disposed through the opening in each disk to form a stack of the disks having a longitudinal axis substantially parallel to the axis of the frame. The apparatus further includes at least one endless belt for transferring a fillet, wherein the endless belt has a top surface and a lower surface opposite the top surface. A floating feed roller is positioned above the top surface of the endless belt, and a nose roller is positioned beneath the top surface of the endless belt, thereby defining a space between the floating feed roller and the nose roller to allow the fillet to pass therethrough to the stack of the disks to be processed.
In yet another aspect, the present invention provides a pin bone removal apparatus comprising means for positioning the fillet over a stack of a plurality of disks at a first position, each disk having a center and a periphery that circumscribes the center to form an opening, the stack of the disks having a longitudinal axis extending through the centers of the disks, and means for moving the stack of the disks in a first direction longitudinally at a first speed and the fillet relative to each other so that the pin bone is disposed intermediate the periphery of two adjacent disks in the stack and removed thereby as the pin bone engages a portion of the periphery of each of the two adjacent disks, and moving the stack of the disks at a second speed in a second direction opposite the first direction substantially back toward the first position, wherein the second speed and the first speed are different.
In a further aspect, the present invention provides a method of removing a pin bone from a fillet comprising the steps of positioning the fillet over a stack of a plurality of disks at a first position, each disk having a center and a periphery that circumscribes the center, the stack of the disks having a longitudinal axis extending through the centers of the disks, moving the stack of the disks in a first direction longitudinally at a first speed and the fillet relative to each other so that the pin bone is disposed intermediate the periphery of two adjacent disks in the stack and removed thereby as the pin bone engages a portion of the periphery of each of the two adjacent disks, and returning the stack of the disks at a second speed toward the first position, wherein the second speed and the first speed are different.